Vegetable oil-based printing ink and method for producing same

ABSTRACT

Vegetable oil-based printing inks having at least about 20 poises are formulated by admixing a vegetable oil-based printing ink vehicle having an effective amount of polymerized vegetable oil and an effective amount of unpolymerized vegetable oil sufficient to provide the vegetable oil-based printing ink with a viscosity of at least about 20 poises, and an effective amount of colorant to provide the vegetable oil-based printing ink with a predetermined color. Methods for reclaiming residual vegetable oil-based printing ink from a printing press and polymerizing the vegetable oil component of the vegetable oil-based printing ink vehicle are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 09/456,009, filedDec. 7, 1999, entilted “VEGETABLE OIL-BASED PRINTING INK AND METHOD FORPRODUCING SAME,” now U.S. Pat. No. 6,265,594; which is a continuation ofU.S. Ser. No. 09/128,840, filed Aug. 4, 1998, entitled “VEGETABLEOIL-BASED PRINTING INK AND METHOD FOR PRODUCING SAME,” now abandoned;and which is a continuation of U.S. Ser. No. 08/711,577, filed Sep. 10,1996, entitled “VEGETABLE OIL-BASED PRINTING INK AND METHOD FORPRODUCING SAME,” now U.S. Pat. No. 5,788,752.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to printing inks and, moreparticularly, but not by way of limitation, to a vegetable oil-basedprinting ink for lithographic printing presses.

In one aspect, the present invention relates to a method of reclaimingresidual vegetable oil-based printing ink from a printing press duringthe cleaning of a printing press by recovering residual vegetableoil-based printing ink from printing presses and utilizing suchrecovered residual vegetable oil-based printing ink in the formulationof the vegetable oil-based printing ink.

In another aspect, the present invention relates to a method forpolymerizing a vegetable oil component of such vegetable oil-basedprinting ink.

2. Brief Description of the Prior Art

Printing ink produced in the past has been petroleum-based, typicallycomprised of 15-20% carbon black as the pigment, 15-25% hydrocarbon oralkyd resin, and 50-70% mineral oil solvent. Nearly 500 millionkilograms of inks for these applications are produced domestically eachyear. This volume of production represents a substantial consumption ofpetroleum-based ingredients. The petroleum oil shortage in themid-1970's stimulated research to find alternatives to mineral oil andother petroleum products in ink formulations.

In the early 1980's, the American Newspaper Publishers Association(“ANPA”) directed a research effort on developing a non-petroleum-basedvehicle for newspaper inks. In response to the ANPA directives, numerousapproaches were taken resulting in the formulation of vegetableoil-based ink using a combination of petroleum based ingredients and soybean oil. Widespread commercial acceptance of the petroleum based/soybean oil ink has been inhibited, however, by the cost, which is 50-70%more than traditional petroleum-based black inks. Additionally, althoughthese inks tout the 100% soy bean oil ingredient, petroleum derivativesare still added to the formulation of the ink to achieve certaincharacteristic standards.

Despite these advances made by the ANPA and others, the industry hascontinued to seek a non-petroleum-based printing ink which would “(1) becost competitive with petroleum-based inks; (2) not require anypetroleum-derived component; (3) resist ruboff on hands and clothing;and (4) enable formulation over a wide range of viscosities required byvarious printing applications.

In 1991, U.S. Pat. No. 5,122,188 was granted wherein Nitrogen wasemployed to produce a 100% vegetable oil-based printing ink with nopetroleum derivatives. Problems have been encountered in employing thenon-petroleum derivatives when scaling up for commercialization of theprocess. The problems that persist in the use of vegetable oil-basedinks for lithographic printing presses include lengthy drying time,environmental waste concerns, high production costs, difficulty in cleanup, and high material costs.

The present invention solves the above problems that exist in priorvegetable oil-based printing inks by providing a vegetable oil-basedprinting ink system that lowers material and production costs.Additionally, the vegetable oil-based printing ink is recyclable andremovable directly from the printing presses for reuse as a component inthe formulation of the vegetable oil-based printing ink. A significantbenefit in the current invention is the ability to polymerize vegetableoil in the same process to form high quality recyclable vegetableoil-based printing inks having a wide range of viscosities. Thevegetable oil-based printing ink eliminates dependance on petroleumproducts and provides competitive performance characteristics.

SUMMARY OF THE INVENTION

According to the present invention, vegetable oil-based printing inksare provided which can be produced in a wide range of viscosities whilelowering costs and recycling ink waste. The vegetable oil-based printinginks of the present invention are produced by admixing colorant with avegetable-oil based printing ink vehicle (hereinafter “vehicle”). Thevehicle comprises a polymerized vegetable oil and may comprise anunpolymerized vegetable oil produced by admixing from about 5 to about100 weight percent of polymerized vegetable oil and from 0 to about 95weight percent unpolymerized vegetable oil sufficient to achieve aviscosity of at least 20 poises.

The vegetable oil-based printing ink may be reclaimed directly from theprinting press by applying unpolymerized vegetable oil to the printingpress to dissolve residual vegetable oil-based printing ink therebyremoving the residual vegetable oil-based printing ink from the printingpress and forming a contaminated printing ink. The contaminated printingink is filtered to remove particulate matter thereby yielding asubstantially particulate free residual printing ink. The substantiallyparticulate free residual printing ink is then admixed with an effectiveamount of colorant and an effective amount of fresh vegetable oil basedprinting ink vehicle to provide a vegetable oil-based printing ink withat least about 20 poises and a predetermined color.

The polymerized vegetable oil having a viscosity of at least about 20poises employed in the vegetable oil-based ink vehicle is produced bypolymerizing vegetable oil in an evacuated steady state or continuousflow reactor system. More specifically, polymerization of theunpolymerized vegetable oil is achieved by heating unpolymerizedvegetable oil under vacuum, to a temperature of from about 150 to about210 degrees C. for a period of time effective to provide a substantiallyoxygen free unpolymerized vegetable oil. The substantially oxygen freeunpolymerized vegetable oil is then heated under vacuum to a temperatureof from about 280 to about 330 degrees C. for a period of time effectiveto provide a substantially colorless polymerized vegetable oil having aviscosity of at least about 20 poises.

An object of the present invention is to provide vegetable oil-basedprinting inks having a viscosity of at least 20 poises adaptable for usewith a wide variety of printing presses.

Another object of the invention, while achieving the before-statedobjective, is to provide a method of reclaiming residual vegetableoil-based printing ink from printing presses.

Yet another object of the present invention, while achieving thebefore-stated objectives, is to provide a method of cleaning a printingpress wherein the waste cleaning solution is biodegradable and therebysubstantially reduces the environmental impact of disposal of the waste.

Another object of the invention, while achieving the before-statedobjectives, is to provide a method for polymerizing vegetable oil havinga wide range of viscosities.

Other objects, advantages, and features of the present invention willbecome obvious to those skilled in the art upon reading the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of a system for preparingpolymerized vegetable oils in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Definitions

The term “colorant” as used herein is to be understood to be pigmentsthat provide the vegetable oil-based printing ink with the desiredcolor. The term “colorant” refers to commercially available powderedpigments, dispersions of such pigments including commercially availableflushes, and flushes produced from residual vegetable oil-based printingink removed from printing presses as will be defined and discussed indetail herein after.

The term “vegetable oil-based printing ink vehicle” or “vehicle” as usedherein is understood to be a system that carries and dissolves pigmentso that it has sufficient flow characteristics to disperse the pigmentonto paper. The “vehicle” as used herein comprises an admixture of from5 to about 100 weight percent polymerized vegetable oil with from 0 toabout 95 weight percent unpolymerized vegetable oil sufficient toachieve a vegetable oil-based vehicle having a predetermined viscosityof at least 20 poises. The vegetable oil used in the formulation of thevehicle may be polymerized or unpolymerized vegetable oils such ascommercially available soybean oil, cottonseed oil, canola oil,sunflower oil, safflower oil, and mixtures thereof.

The term “printing ink flush” or “flush” as used herein refers topigment blends utilized in the vegetable oil-based printing ink torender the ink the desired color. The term “flush” means dispersions ofpigments including commercially available flushes and flushes producedfrom residual vegetable oil-based printing ink removed from printingpresses as will be defined and discussed in detail herein after. The“flush” may be used as a component in producing a vegetable oil-basedprinting ink having the desired color and viscosity.

Background

Vegetable oil-based printing inks having a viscosity of at least about20 poises of the present invention can be formulated by admixing avehicle with an effective amount of colorant sufficient to provide avegetable oil-based printing ink having the desired color and viscosity.The amount of vegetable oil-based printing ink vehicle employed in theformulation of the vegetable oil-based printing inks having a viscosityof at least about 20 poises can vary widely and will depend upon thedesired viscosity of the vegetable oil-based printing ink, theproperties of the colorant and the type of press used for printing usingthe vegetable oil-based printing inks. Generally, however, the amount ofvehicle employed in the formulation of the vegetable oil-based printingink having a viscosity of at least about 20 poises will be an amountsufficient to provide the vegetable oil-based printing ink with fromabout 60 to about 95 weight percent of the vehicle.

The vehicle, as stated previously, desirably is an admixture of fromabout 5 to about 100 weight percent polymerized vegetable oilpolymerized vegetable oil and from 0 to about 95 weight percentunpolymerized vegetable oil sufficient to provide the vegetableoil-based printing ink with a viscosity of at least 20 poises. Theamount of polymerized and unpolymerized vegetable oil employed in theformulation of the vegetable oil-based printing inks having a viscosityof at least about 20 poises can vary widely and will depend upon thedesired viscosity of the vegetable oil-based printing ink, theproperties of the colorant and the type of press used for printing usingthe vegetable oil-based printing inks. Generally, however, the amount ofpolymerized and unpolymerized vegetable oil employed in the formulationof the vegetable oil-based printing ink having a viscosity of at leastabout 20 poises will be an amount sufficient to provide the vegetableoil-based printing ink vehicle with from about 5 to about 100 weightpercent of the polymerized vegetable oil and from about 0 to about 95weight percent of the unpolymerized vegetable oil.

Any suitable vegetable oil which is compatible with the colorant andwhich can be polymerized to provide the vegetable oil constituent havingthe desired viscosity may be employed as the vegetable oil component ofthe vegetable oil-based printing inks of the present invention. Examplesof such vegetable oils are soybean oil, cottonseed oil, canola oil,sunflower oil, safflower oil, and mixtures thereof. Desired results canbeen achieved wherein the vegetable oil utilized is a commerciallyavailable soybean oil.

The amount of colorant employed in the vegetable oil-based printing inkshaving a viscosity of at least about 20 poises is that amount necessaryto render the vegetable oil-based printing ink with the desired color.Further, the amount of colorant employed will vary depending upon thecolor of the pigment in the colorant and the desired drying time of thevegetable oil-based ink because it has been found that the amount andstate of the colorant present in vegetable oil-based printing inks hasan effect on the drying time of the vegetable oil-based printing inks.That is, the more colorant present in the vegetable oil-base printinginks, the less time required to dry such inks. Generally, however, theamount of colorant admixed with the polymerized vegetable oil to producethe vegetable oil-based printing inks will be an amount sufficient toprovide the vegetable oil-based inks with from about 5 to about 40weight percent colorant.

Any suitable colorant containing a pigment capable of imparting thedesired color and printing characteristics to the vegetable oil-basedinks of the present invention can be employed in the formulation of suchinks. For example, the colorant may consist of a powdered pigment, apigment dispersion, a commercially available ink flush comprisingpremixed vegetable oil and pigment or flushes prepared by employingreclaimed residual vegetable oil-based printing ink removed fromprinting presses as will be discussed in detail hereinafter. Desiredresults can be been obtained wherein the colorant is a red pigment, bluepigment, yellow pigment, black pigment, and combinations thereof. Itshould be understood that the colorant may be combined to achieve otherdesired colors. Examples of commercially available colorant which can beused from commercially available ink flushes are Lithol Rubine Bio-SetFlush®, Diarylide Yellow AAA S/O Bio-Set Flush®, and CopperPhthalocyanine Blue G/S Bio-Set Flush®. Desired results can also beenobtained where the colorant is a pigment selected from newspaperpigments specified by the News Paper Association of America such asCiba-Geigy Irgalite Blue LGLD.

The vegetable oil-based printing ink can further comprise an effectiveamount of additives and other auxiliary components, for example resins,plasticizers, stabilizers, drying agents, and others known to the art toimprove the quality of the ink. When utilizing additive(s), theformulation of the vegetable oil-based printing ink contains from about50 to about 95 weight percent vegetable oil-based printing ink vehicle,from about 5 to about 40 weight percent colorant and 0 to about 10weight percent additives, the vegetable oil based printing ink vehiclecomprising from about 5 to about 100 weight percent polymerizedvegetable oil and from 0 to about 95 weight percent unpolymerizedvegetable oil. Any suitable additive capable of imparting the desiredcharacteristics for printing ink that is compatible with the vegetableoil-based inks of the present invention can be employed in theformulation of such inks. Various additives used in printing inks and inparticular lithographic ink compositions are well known in the art asdisclosed for example in The Printing Ink Manual, Fifth Edition, editedby R. H. Leach, R. J. Pierce, etc., and published by Glue Print, thesubstance of which is incorporated herein by reference.

The vegetable oil-based printing ink can further comprise an effectiveamount of preservative compatible with the microbial growth in thevegetable oil-based printing ink. When employing a preservative in theformulation of the vegetable oil-based printing ink, the formulation ofthe vegetable oil-based printing ink contains from about 59 to about 95weight percent of the vegetable oil-based printing ink vehicle, fromabout 5 to about 40 weight percent colorant and 0 to about 1 weightpercent preservative, the vegetable oil-based printing ink vehiclecomprising from about 5 to about 100 weight percent polymerizedvegetable oil and from 0 to about 95 weight percent unpolymerizedvegetable oil. Any suitable preservative compatible with the microbialgrowth of the vegetable oil based printing ink and otherwise compatiblewith the vegetable oil-based printing ink of the present invention canbe employed in the formulation of such inks. Desired results may beobtained wherein the preservative is Zertiary Butyl Hydroxy Quinone.When employing a preservative and additives in the formulation of thevegetable oil-based printing ink, the formulation of the vegetableoil-based printing ink contains from about 49 to about 95 weight percentof the vegetable oil-based printing ink vehicle, from about 5 to about40 weight percent colorant, from 0 to about 10 weight percent additives,and 0 to about 1 weight percent preservative, the vegetable oil-basedprinting ink vehicle comprising from about 5 to about 100 weight percentpolymerized vegetable oil and from 0 to about 95 weight percentunpolymerized vegetable oil.

If desired, one can incorporate a catalytic amount of a catalystcompatible with the vegetable oil-based printing ink and capable ofenhancing polymerization. Any suitable catalyst capable of imparting thedesired characteristics for printing ink that is compatible with thevegetable oil-based inks of the present invention can be employed in theformulation of such inks. Such catalysts are well known in the art so nofurther description of such catalysts are believed necessary.

When employing residual vegetable oil-based printing ink in theformulation of the vegetable oil-based printing inks of the presentinvention, at least a portion of the vegetable oil-based printing inkmay be provided from printing ink removed directly from a printing press(i.e. residual vegetable oil-based printing ink) thereby enhancing theenvironmental benefits derived from the vegetable oil-based printinginks of the present invention. That is, the composition of the vegetableoil-based printing inks provide for easy removal of the residualvegetable oil-based printing ink from printing presses by usingunpolymerized vegetable oil thus eliminating the need to alter thecomposition of the ink to enhance solubility.

To recover residual vegetable oil-based printing ink, which can beemployed in the formulation of a vegetable oil-based printing ink, froma printing press, the press is washed with unpolymerized vegetable oilto dissolve residual vegetable oil-based printing ink in the printingpress. The unpolymerized vegetable oil, desirably comprising theunpolymerized vegetable oil component of the vegetable oil-basedprinting ink, dissolves the residual vegetable oil-based printing inkand produces a contaminated printing ink containing unpolymerizedvegetable oil, residual vegetable oil-based printing ink, andparticulate matter. The contaminated printing ink is then collected andfiltered using a separation process so as to produce a substantiallyparticulate free residual printing ink.

The substantially particulate free residual printing ink may then beused as a component in the formulation of the vegetable oil-basedprinting ink of the present invention. The substantially particulatefree residual printing ink comprises vehicle and colorant as required inthe formulation of the vegetable oil-based printing ink. The removalprocess, however, typically dilutes the amount of colorant in thesubstantially particulate free residual printing ink. To reclaim thesubstantially particulate free residual printing ink and obtain avegetable oil-based printing ink, the substantially particulate freeresidual printing ink is admixed with an effective amount of colorantand vehicle to formulate a vegetable oil-based printing ink having aviscosity of at least 20 poises and a predetermined color. The amount ofcolorant and/or vehicle admixed with the substantially particulate freeresidual printing ink can vary widely and will depend upon the desiredviscosity of the vegetable oil-based printing ink. Generally, however,the amount of colorant and/or vehicle admixed with the substantiallyparticulate free residual printing ink employed in the formulation ofthe vegetable oil-based printing ink will be an amount sufficient toprovide the vegetable oil-based printing ink with a viscosity of atleast 20 poises, from about 5 to about 40 weight percent of colorant,and from about 60 to 95 weight percent vehicle.

Because the printing ink can be removed directly from the printing pressusing unpolymerized vegetable oil, and because the vegetable oil-basedprinting ink can be produced by using residual vegetable oil-basedprinting ink recovered from the press, the residual vegetable oil-basedprinting ink can be collected and recycled, thereby enhancingenvironmental benefits.

The method of reclaiming residual vegetable oil-based printing ink mayalso be used to produce a flush. Once the substantially particulate freeresidual vegetable oil-based printing ink is collected, it may beadmixed with an effective amount of colorant and an effective amount ofvehicle to produce a printing ink flush. Typically the concentration ofcolorant present in the printing ink flush is of a much higherconcentration than the amount of colorant present in the vegetableoil-based printing ink. Additionally, printing ink flush does notrequire, but does permit the use of polymerized vegetable oil in theformulation.

Once the residual vegetable oil-based printing ink is removed from theprinting press, the printing press is washed with a biodegradablecleaning composition. The biodegradable cleaning solution is introducedto the printing press to remove residual unpolymerized vegetable oil andrecover a biodegradable waste cleaning solution comprising thebiodegradable cleaning solution, residual unpolymerized vegetable oil,and particulate matter. The biodegradable waste cleaning solution isdisposable in a public sewer system. Desired results can been obtainedwhere residual vegetable oil-based printing ink is gathered from a WebOff-Set printing press by the above mentioned method using abiodegradable cleaning fluid comprising an admixture of an effectiveamount of Dowanol Dipropylene Glycol Methyl Ether (DPM), an effectiveamount of nonionic surfactant such as commercially available X-100®, andan effective amount of deodorant sufficient to remove residual vegetableoil-based printing ink from the printing press. Desired results can beobtained wherein the formulation comprises 89.06 weight percent DowanolDPM, 10.03 weight percent X-100, and 0.91 weight percent lemon scent.The biodegradable waste cleaning solution can also be a formulationcomprising an admixture of an effective amount of Dowanol DPM, aneffective amount of nonionic surfactant such as commercially availableX-100®, an effective amount of nonionic surfactant such as Witconate 90kflakes, and an effective amount of water sufficient to remove residualvegetable oil-based printing ink from the printing press. Desiredresults can be obtained wherein the formulation comprises 6.0 weightpercent DPM, 7.0 weight percent X-100, 4.2 weight percent Witconate 90kflakes, and 82.80 weight percent water.

Referring now to the drawings, and more particularly to FIGURE, anevacuated continuous flow reactor system 10 for polymerizing vegetableoil in accordance with the present invention is diagrammaticallyillustrated. The evacuated continuous flow reactor 10 producespolymerized vegetable oils having a wide range of viscosities for use invegetable oil-based printing inks. The polymerization process is able toyield a range of viscosities of from at least about 20 poises all theway up to the gel state. Further, the vegetable oil-based printing inksformed from the polymerized vegetable oils eliminate petroleum additivesand waste by-products. The continuous flow reactor system 10 provides acontinuous production system which is a cost effective and efficientmeans for producing polymerized vegetable oil.

The evacuated continuous flow reactor 10 comprises a feeder tank 12containing unpolymerized vegetable oil, a heat exchanger 16, a firstreactor 20, a second reactor 26, and a receiving vessel 36. Theevacuated continuous flow reactor 10 further comprises evacuation pumps22, 28, 42, and 48, and storage tank 46. When the evacuated continuousflow reactor 10 is in production mode and evacuation pumps 22, 28, 42,and 48 are turned on, the unpolymerized vegetable oil continuouslypasses from the feeder tank 12 through a conduit 14 into the heatexchanger 16 and polymerized oil continuously passes through theevacuated continuous flow reactor 10 until it reaches the storage tank46. The pressure differential between the evacuation pumps 22, 28, 42,and 48 acts to force the vegetable oil through the evacuated continuousflow reactor system 10 as the pumps place a vacuum on the vegetable oilto remove oxygen. The unpolymerized vegetable oil is heated in the heatexchanger 16 by heat exchange contact with the polymerized vegetable oilas it simultaneously passes through the heat exchanger 16 in a mannerwhich will be described further. The unpolymerized vegetable oil isheated in the heat exchanger 16 to a temperature of from about 80 toabout 100 degrees C. The unpolymerized vegetable oil passes from theheat exchanger 16 through conduit 18 to the first reactor 20 wherein theunpolymerized vegetable oil is heated and stirred under vacuum to atemperature of from about 150 to about 210 degrees C., and moredesirable from about 160 to about 180 degrees C. The unpolymerizedvegetable oil is heated and stirred under vacuum in the first reactor 20for a period of time sufficient to permit evacuation pump 22 tosubstantially remove the oxygen from the unpolymerized vegetable oil.The time that the unpolymerized vegetable oil remains in the firstreactor is determined by the volume and the flow rate. Generally, theunpolymerized vegetable oil remains in the first reactor 20 for aresident time of from about one to about three hours.

Next, the unpolymerized vegetable oil passes from the first reactor 20through conduit 24 into the second reactor 26. The unpolymerizedvegetable oil is heated in the second reactor 26 to a temperature offrom about 280 to about 330 degrees C. for a period of time effective topolymerize the unpolymerized vegetable oil, more desirable from about300 to about 320 degrees C. The unpolymerized vegetable oil is heatedand stirred under vacuum so that a substantially oxygen free polymerizedvegetable oil is provided in the second reactor 26. The time that theunpolymerized vegetable oil remains in the second reactor is determinedby the volume and the flow rate sufficient to attain the desiredviscosity. Generally, the unpolymerized vegetable oil remains in thesecond reactor 26 for a resident time of from about 1 to about 3 hours.As the unpolymerized vegetable oil is being heated and stirred to formthe polymerized vegetable oil in the second reactor 26, evacuation pump28 applies a vacuum to the unpolymerized vegetable oil to further removeany remaining entrained oxygen. The unpolymerized vegetable oil istransformed into polymerized vegetable oil and, when valve 30 is opened,at least a portion of the polymerized vegetable oil is passed from thesecond reactor 26 through conduit 32 to the heat exchanger 16 and theremainder passes direction from the second reactor through conduit 40 tothe receiving vessel 36. The polymerized vegetable oil is cooled in theheat exchanger 16 by heat exchange contact with the unpolymerizedvegetable oil simultaneously passing through the heat exchanger 16. Thepolymerized vegetable oil is cooled to a temperature less than about 280degrees C. The polymerized vegetable oil then passes from the heatexchanger 16 through conduit 34 to the receiving vessel 36.

When valves 30 and 38 are both opened, a portion of polymerizedvegetable oil passes from the second reactor 26 through conduit 32 tothe heat exchanger 16 and a portion of the polymerized vegetable oilpasses directly from the second reactor 26 through conduit 40 to thereceiving vessel 36 without passing through heat exchanger 16. It shouldbe noted that when valve 38 is opened and valve 30 is closed, thepolymerized vegetable oil passes directly from the second reactor 26through conduit 40 to the receiving vessel 36 without passing throughheat exchanger 16.

The polymerized vegetable oil remains in the receiving vessel 36, undervacuum from pump 42, and the viscosity is measured. After the desiredviscosity is attained, the polymerized vegetable oil passes from thereceiving vessel 36 through conduit 44 and is then collected in thestorage tank 46. Pump 48 applies a vacuum to the polymerized vegetableoil in the storage tank 46.

It should be understood that polymerization of the vegetable oil mayalso be achieved using a batch process wherein the substantially oxygenfree polymerized vegetable oil having a viscosity of at least about 20poises is produced by heating unpolymerized vegetable oil under vacuumto a predetermined temperature for a period of time effective to removeentrained oxygen from the unpolymerized vegetable oil and produce asubstantially oxygen free unpolymerized vegetable oil. The unpolymerizedvegetable oil is heated and stirred under vacuum to a temperature offrom about 280 to about 330 degrees C. for a period of time effective toremove entrained oxygen and to produce a polymerized vegetable oilhaving a viscosity of at least about 20 poises. Longer periods of timemay be required wherein a larger amount of vegetable oil is beingpolymerized and higher viscosities are desired.

As previously stated, the vegetable oil-based printing ink having aviscosity of at least about 20 poises comprises the above mentionedvehicle and an effective amount of colorant sufficient to provide thevegetable oil-based printing ink with the desired color.

In order to more fully describe the present invention, the followingexamples are set forth. However, it is to be understood that theexamples are for illustrative purposes only and are not to be construedas unduly limiting the scope of the present invention.

EXAMPLE 1

A vegetable oil-based printing ink having a viscosity of from about 235to about 245 poises may be prepared by admixing the followingingredients:

15 weight percent Ciba-Geigy Irgalite Blue LGLD colorant and

85 weight percent vehicle having a viscosity of about 250 poisescomprising:

80 weight percent polymerized soybean oil having a viscosity of about1247 poises

20 weight percent unpolymerized soybean oil

The polymerized vegetable oil having at least 20 poises and morepreferably about 1247 poises may be produced by the following procedure:

Two liters of unpolymerized soybean oil may be placed in a 5 liter roundbottom flask under vacuum of 26 inches of mercury. The unpolymerizedsoybean oil may then be heated for approximately two hours until asteady temperature of 305 degrees C. is reached. The temperature maythen be maintained at 305 C. for from about 4 to about 5 hours untilpolymerization of the unpolymerized soybean oil is achieved. Thepolymerized soybean oil may then be cooled and the viscosity measuredwith a Brookfield viscometer at about 25 C. A viscosity of from about1200 to about 1250 poises may then be obtained.

EXAMPLE 2

A vegetable oil-based printing ink may be prepared by admixing thefollowing ingredients:

87.51 weight percent Vehicle comprising:

65.63 weight percent Polymerized Soybean Oil

21.88 weight percent Unpolymerized Soybean Oil

12.50 weight percent Copper Phthalocyanine Blue GIS Bio-Set flush®

The vegetable oil-based printing ink may then be applied to a sheet ofpaper thereby exhibiting good color definition.

EXAMPLE 3

A vegetable oil-based printing ink may be prepared by mixing thefollowing ingredients:

81.33 weight percent Vehicle comprising:

50.64 weight percent Polymerized Soybean Oil

30.69 weight percent Unpolymerized Soybean Oil

18.67 weight percent Lithol Rubine Bio-Set Flush®

The vegetable oil-based printing ink may then be applied to a sheet ofpaper thereby exhibiting good color definition.

EXAMPLE 4

Printing ink may be reclaimed from a Web Off-Set printing pressaccording to the following procedure:

1. Clean the blanket roller by applying unpolymerized soybean oil to ablanket roller of the press and wipe the roller clean using a sponge orroller. Residual soybean oil is removed from the blanket roller bywiping the roller with a dry rag.

2. Clean the ink rollers by removing unused printing ink before cleaningthe press. Pour unpolymerized soybean oil onto the roller while therollers are rotating at a slow speed. The unpolymerized oil is addeduntil all the ink has been removed. The waste ink is then removed fromthe ink container and stored in a can for recycling.

3. The ink collected by the above process is collected and filteredthrough a coarse filter using a suction funnel to remove particulatematter. The concentration of pigment contained in the filtered waste inkmay be determined by using a draw-down strip. The concentration of thewaste ink is then adjusted to achieve the desired weight percent ofcolorant by adding colorant to the waste ink. The waste ink may behomogenized for about 10 minutes to obtain a reading of less than 4 on agrind gauge. The desired weight percent of colorant in the waste ink isfrom about 5 to about 40 weight percent colorant.

EXAMPLE 5

The following procedure may be used for polymerizing soybean oil in theevacuated continuous flow reactor system (FIG. 1). The evacuatedcontinuous flow reactor is placed in production mode according to thefollowing starting conditions:

Feeder Vessel—1000 ml unpolymerized soybean oil

1st Reactor Vessel—1500 ml unpolymerized soybean oil

2nd Reactor Vessel—3000 ml unpolymerized soybean oil

Receiving Vessel—200 ml unpolymerized soybean oil

P1—1st Reactor evacuation pump pressure 25 in.

P2—2nd Reactor evacuation pump pressure 25.5 in.

P3—Receiving Vessel evacuation pump pressure 25 in.

P4—Storage Tank evacuation pump pressure 0 in.

Flow—Initial Flow Rate—0 ml/min.

The evacuation pumps are pressurized and the second reactor is preheatedto a temperature of about 303 degrees C. to begin the flow of thesoybean oil through the evacuated continuous flow reactor system. Oncethe temperature of 303 degrees C. in the second reactor is achieved andthe pumps are turned on, then the unpolymerized soybean oil will beginto flow. The soybean oil may flow through the evacuated continuous flowreactor system according to the following conditions:

Evacuation Pumps 2nd Reaction Flow Rate P1 P2 P3 P4 Reactor ViscosityTime (min) ml/min in in in in Temp (C.) Poises 0 0 20 21.5 26.5 28 30316 60 10 13 15 21.5 28 310-318 16.01 100 16 15 19 21 28 310-318 17.4 1578 15 19 21 28 310-318 21.9 288 5 15 19 21 28 310-318 39.1

The second reactor is heated and stirred to a temperature of from about310 to about 318 degrees C. to begin polymerization of the soybean oil.As the soybean oil is heated, evacuation pumps 1-4 remove oxygen fromthe soybean oil thereby providing a substantially oxygen freepolymerized soybean oil. As the soybean oil is polymerized, theviscosity of the soybean oil increases. At each of the time intervalsabove, 500 ml of the polymerized soybean oil is collected and theviscosity measured on a Brookfield viscometer. The flow rate may also bedetermined by the time it takes for 500 ml to pass from the receivingvessel to the storage tank. As shown in the table above, a reaction timeof 288 minutes at the given flow rates, pressures, and temperaturesthrough the evacuated continuous flow reactor system yields apolymerized soybean oil having a viscosity of 39.1 poises. It should beunderstood that the pressures indicated in the above table may vary fromabout 3 to about 7 inches during the polymerization process.

Changes may be made in the construction and the operation of the variouscomponents, elements and assemblies described herein and changes may bemade in the steps or the sequence of steps of the methods describedherein without departing from the spirit and scope of the invention asdefined in the following claims.

What is claimed:
 1. A method of reclaiming residual vegetable oil-basedprinting ink from a printing press during the cleaning of a printingpress, comprising: a. applying unpolymerized vegetable oil to a printingpress in an amount effective to dissolve residual vegetable oil-basedprinting ink therefrom thereby producing a contaminated printing inkcomprising unpolymerized vegetable oil, residual vegetable oil-basedprinting ink and particulate matter; b. filtering the contaminatedprinting ink to remove particulate matter and provide a substantiallyparticulate free residual printing ink; c. admixing an effective amountof colorant with an effective amount of substantially particulate freeresidual printing ink to provide a residual vegetable oil-based printingink having a predetermined viscosity and a predetermined weight percentof colorant; and d. disposing of the biodegradable waste cleaningsolution in a public sewer system.